RAN Paging eDRX Coordination for RRC Inactive Mobile Terminals

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Solution Overview

Problem

Existing NR specifications lack a mechanism for RAN paging when a terminal compatible with eDRX transitions to the RRC_INACTIVE state, particularly for terminals likely to move, such as those mounted on vehicles.

Innovation Solution

A base station with a control unit for RAN paging processing and a transmitting unit that sends RAN paging information elements, including eDRX configuration, via the Xn interface to other base stations, allowing flexible PTW start positions and monitoring control channel candidates during specific periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If eDRX is implemented for power-saving terminals in NR, then power consumption is reduced, but RAN paging mechanism is missing for terminals in RRC_INACTIVE state

Engineering Contradiction:

Improvepower consumptionVSAvoidRAN paging functionality

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The base station stores eDRX configuration information in advance before the terminal enters RRC_INACTIVE state. When downlink data arrives, the base station retrieves the stored eDRX configuration to determine the appropriate paging time window, enabling RAN paging to function correctly for eDRX terminals in inactive state

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism where the base station acts as a mediator between the core network and eDRX terminals in RRC_INACTIVE state. The base station receives downlink data from the core network, retrieves stored eDRX configuration, determines the paging time window, and transmits paging information at the appropriate time, thus enabling indirect communication with sleeping terminals

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If terminal transitions to RRC_INACTIVE state for mobility, then mobility is supported, but RAN paging mechanism for eDRX terminals is not provided

Engineering Contradiction:

Improvemobility supportVSAvoidRAN paging functionality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The base station performs preliminary action by storing eDRX configuration information before the terminal transitions to RRC_INACTIVE state. This advance preparation ensures that when the terminal moves and downlink data arrives later, the base station can immediately retrieve the stored configuration and execute RAN paging without requiring the terminal to be in connected state

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamic adaptation by allowing the base station to flexibly determine paging time windows based on retrieved eDRX configuration. The system dynamically adjusts paging behavior according to the terminal's eDRX parameters, enabling RAN paging to function effectively for mobile terminals in inactive state with varying mobility patterns

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12574896B2Base station and wireless communication method

Publication Date: 2026.03.10 DENSO CORP

AI summary

A base station includes a control unit that controls radio access network (RAN) paging processing for a terminal in a radio resource control inactive (RRC_INACTIVE) state and a transmitting unit that transmits, to any other base station connected by a given interface, RAN paging information elements including configuration information for extended discontinuous reception (eDRX) in the RAN paging processing for the terminal.